public List<SwitchTarget> getTargets(boolean onlyVisible) {
   Collection<GridCellImpl> cells = myPlaceInGrid2Cell.values();
   ArrayList<SwitchTarget> result = new ArrayList<SwitchTarget>();
   for (GridCellImpl each : cells) {
     result.addAll(each.getTargets(onlyVisible));
   }
   return result;
 }